A mail creation system or a “mailpiece inserter” is commonly employed for producing mailpieces intended for mass mail communications. Such mailpiece inserters are typically used by organizations such as banks, insurance companies and utility companies for producing a large volume of specific mail communications where the contents of each mailpiece are directed to a particular addressee. Also, other organizations, such as direct mailers, use mailpiece inserters for producing mass mailings where the contents of each mailpiece are substantially identical with respect to each addressee.
In many respects, a typical inserter resembles a manufacturing assembly line. Sheets and/or other raw materials (i.e., a web of paper stock, enclosures, and envelopes) enter the inserter as inputs. Various modules or workstations of the inserter work cooperatively to process the sheets until a finished mail piece is produced. Typically, inserter systems prepare mail pieces by arranging preprinted sheets of material into a collation, i.e., the content material of the mail piece, on a transport deck. The collation of preprinted sheets may continue to a chassis module where additional sheets or inserts may be added based upon predefined criteria, e.g., an insert being sent to addressees in a particular geographic region. Subsequently, the collation may be folded and placed into envelopes. Once filled, the envelopes may be closed, sealed, weighed, and/or sorted. A postage meter may then be used to apply postage indicia based upon the weight and/or size of the mail piece.
These inserters typically require the use of “preprinted” sheets which are presented to the various downstream devices by a feed module for subsequent processing. That is, a mailpiece job run is printed to produce an “ordered” stack of mailpiece content material which may be fed to the mailpiece inserter. Scan codes disposed in the margin of the first or last sheet of each mailpiece document provide the instructions necessary to process the mailpiece, i.e., whether additional inserts will be added, how the content material is to be folded (C-fold, Z-fold, etc.) and/or what size envelop will the content material be contained. To facilitate communication of these instructions, a user computer and a printing device are typically network-connected to the mailpiece inserter such that scan codes can be easily printed and interpreted.
More recently, printers have been integrated with mailpiece inserters so that mailpiece content material may be supplied “on-demand”, and/or “just-in-time”. Examples of inserters having integrated printers include the DI 900 and DI 950 desktop mailpiece inserters manufactured by Pitney Bowes Inc., located in Stamford, Conn. To facilitate throughput, a sheet or page buffer is commonly employed between the printer and inserter modules. In FIG. 1, a conventional page buffer 100 is schematically depicted and interposed between a printer 110 and a chassis module of a mailpiece inserter 112. The page buffer 100 communicates with a system controller 114 to monitor/track the throughput of pages 116 processed by the mailpiece inserter 112. Specifically, the page buffer 100 receives printed pages 116 from the printer 110 and includes a plurality of sequential page stations 118a, 118b, 118c, 118d, 118e disposed along a serial feed path. Position sensing devices 120 are located at or along each of the page stations 118a, 118b, 118c, 118d, 118e to monitor the rate that printed pages 116 enter or leave the page buffer 100. Further, the sensing devices 120 are operative to issue position signals 122 to the system controller 114 such that the inserter 110 may determine whether a page or sheet 116 is positioned at a particular one of the page stations 118a, 118b, 118c, 118d, 118e or whether the page station is available for receipt of another printed page 116.
The rate of change of the position signals 122 (i.e., the signals issued by the page buffer 100) may be used by the controller 114 to determine the throughput that content material is processed. Fundamentally, the “throughput” or “throughput rate” is the magnitude at which sheet material is processed, whether in terms of a steady number of “sheets per unit time”, bundles of sheets (e.g., bundles of five (5) sheets requested every several seconds) or a non-steady flow of sheets. Generally, it is the objective of the system controller 114 to drive the printer 110 to generate content material, i.e., printed pages 116 at a rate consistent, or commensurate, with the rate of processing by other downstream devices of the mailpiece inserter 112. Therefore, as pages are processed by the inserter 112, the controller 114 issues a request signal 124 to the printer 112 to generate additional pages 116.
The design of a page buffer is influenced by a variety of factors including: (i) the space envelope (i.e., length and height availability) of a mailpiece (ii) the number of page stations desired/required, (iii) the travel/conveyor distance from the printer to the inserter, (iv) the processing or throughput speed of the printer as compared to the inserter (i.e., can one module print/process pages faster, slower or at the same rate as the other module), and (v) other unique requirements such as whether pages must be inverted as a result of duplex or dual-sided printing. With respect to the page buffer described above, five (5) page stations are employed and spaced serially end-to-end. Assuming that the page stations accommodate conventional 8.5″×11.0″ letter-size pages, the minimum conveyer or feed path length is approximately five feet (5′), i.e., five times the length of each station.
The page buffer 100 described above accommodates the length of the feed path by incorporating an upper turn-around section 100T, i.e., a vertical portion extending above the printer 110. However, should the design envelope of the page buffer not facilitate or accommodate the upper turn-around section 100T, or require additional page stations, (i.e., the addition of two (2) or three (3) page stations for a total of eight (8) stations), the total length of the feed path may preclude this design option. Even when the design envelope accommodates the overall increase to the page buffer dimensions, the length of the conveyer can impact other design parameters such as the speed, power and acoustics required and/or generated by the page buffer. That is, as the length of the feed path, i.e., from the output tray of the printer to the entrance of the inserter, increases, the conveyer speed must also increase to transport pages in the same time interval. As a consequence, the speed, power and acoustics can exceed threshold levels which place yet other limitations on the design of the page buffer.
In addition to the factors discussed in the preceding paragraph, the throughput capacity of the printer must be compatible, or made compatible, with the throughput of the inserter. In addition to the processing speeds of the respective modules, other factors such as the number of pages being processed at a particular point in time must be considered. For example, any time that the printer is processing pages, other pages, internal to the printer are being processed, including duplex or dual-sided pages. As a consequence, the page buffer must also accommodate or be prepared to queue pages “in process”. As printers process pages at a higher rate, i.e., process more pages on a “per unit time basis”, page buffers must accommodate the additional throughput.
A need, therefore, exists for a page buffer which minimizes the space envelope, reduces the length traveled by, i.e., the feed path of, a printed sheet, and optimizes the number of page stations available for printed pages to be processed by a mailpiece inserter.